1916] Dice: Land Vertebrates of Southeastern Washington 305 



AQUATIC HABITAT AND ASSOCIATION (SAGEBRUSH AREA) 



Beported : 



Ondatra zibethicus osoyoosensis. 



The aquatic association as here considered includes the animals 

 which inhabit the open water of the streams away from the proximity 

 of the shores. Vertebrate .members of the association other than the 

 fishes are few in the region. The Columbia and Snake rivers_are^both 

 swift and during most of the year carry much mud and sand. The 

 lower part of the Walla Walla River is much more sluggish and there 

 are a number of quiet pools. However, there is little aquatic vegeta- 

 tion and few aquatic insects, and the habitat does not appear very 

 suitable for the higher vertebrates. 



AERIAL HABITAT AND ASSOCIATION (SAGEBRUSH AREA) 



Minor: 



Chordeiles virginianus hesperis Tyrannus tyrannus summer, 



summer. Tyrannus verticalis summer. 



Reported: 



Tachycineta thalassina lepida summer. 



The aerial association is considered to be made up of those animals 

 which feed in the air. Most birds fly about in the air more or less, 

 but the association should be limited to those species which carry on a 

 vital activity in the habitat. 



COLUMBIA BASIN PRAIRIE FAUNAL AREA AND FAUNA 



Habitats and Associations : 



Bunchgrass. Water-margin. 



Rocky-slope. Aquatic. 



Cottonwood-willow. Aerial. 



The bunchgrass habitat is dominant over most of Walla Walla 

 County and the western part of Columbia County. In typical parts of 

 the area it covers the entire region with the exception of small areas 

 of rocky slopes and the small amount of surface occupied by the 

 streams and their adjacent habitats. Sagebrush is well developed in 

 local areas on the flats to the west of Lamar and in a few places in the 

 canons near Snake River, but in the typical part of the prairie area 

 sagebrush is clearly subordinate to the bunchgrass and does not form 



